Numerous applications of high pressure continuous processes exist or are under development or in early stages of commercialization. Examples of such processes are hydrothermal and insolvothermal processes e.g. for production of hydrocarbons such as transportation fuels, lubricants or speciality chemicals and gases from carbonaceous materials such as biomass.
The products from the high pressure conversion process typically comprises a pressurized mixture of liquid hydrocarbon compounds; a gas phase comprising carbon dioxide, carbon monoxide, hydrogen, C1-C4 hydrocarbons; a water phase comprising water phase liquid organic compounds and dissolved salts, and optionally suspended solids such as inorganics and/or char and/or unconverted carbonaceous material depending on the specific carbonaceous material being processed and the specific processing conditions.
Various separation techniques are known in the art of oil production. In the area of application of such on hydrocarbons produced from carbonaceous material by use of hydrothermal or solvothermal processes the information on separation is limited. Hydrocarbons produced in this manner will have some characteristics similar to fossil hydrocarbons and will further differ in other areas. The so produced hydrocarbons will, compared to fossil oils, typically be more polarized, have a high viscosity due to a relatively high oxygen content and often show a density close to the density of water. Use of conventional separation methods known from the fossil oil applications on the so produced hydrocarbons has shown that the hydrocarbons after such separation contain too much water and/or too many inorganics for many applications.
Typical the product stream from the high pressure conversion process is depressurized to ambient conditions and cooled to a temperature below the boiling point of water to allow for subsequent separation into the individual phases. However, whereas different techniques have been generically proposed for separation the individual phases including solvent extraction (Downie (WO 2014/197928)), distillation (Downie (WO 2014/197928)), cyclones such as hydrocyclones (Iversen (U.S. Pat. No. 9,212,317-B2), Humfreys (WO2008AU00429), Annee, (EP0204354), Van de Beld (EP1184443)), filtration (Iversen (WO2015/092773), Iversen (U.S. Pat. No. 9,212,317-B2), Annee (EP0204354), Downie (WO 2014/197928), Iversen (WO 2006/117002)), decanting (Yokoyama (U.S. Pat. No. 4,935,567), Modar (WO 81/00855)), centrifugation (Iversen (WO2015/092773), Iversen (U.S. Pat. No. 9,212,317-B2), Iversen (WO2006/117002), Annee (EP0204354)) membrane separation (Modar (WO81/00855), Iversen (WO2006/117002)), only limited details as to the equipment design and separation conditions and operation have been disclosed in the prior art.
For continuous processing water must be extracted from the process in same amount as it is added to the process with the carbonaceous material(-s), catalysts etc. The water phase resulting from such separation processes generally also comprises water phase liquid organic compounds as well as dissolved salts such as homogeneous catalysts in the form of potassium and/or sodium salts and/or suspended solids as well as other components, and requires purification in order to meet environmental standards for the effluent. Besides representing an environmental problem the water phase liquid organic compounds represents a loss of carbon that reduces the oil phase liquid hydrocarbon yield. Elliott et al (U.S. Pat. No. 9,758,728) applies a combined hydrothermal liquefaction and catalytic hydrothermal gasification system to increase overall carbon yields, where the water phase liquid organic compounds are reduced by hydrothermal gasification and converted into a medium-BTU product gas that may be used for process heating. Further purification is proposed by recycling the water phase and/or a solids fraction to the growth stage such as production of algae. However, though the teaching of Elliott et al increases the overall carbon yield, it is achieved via a by-product and the yield of the desired oil phase liquid hydrocarbon product remains unchanged. Further Elliott et al is silent about recovery of homogeneous catalysts in the form of potassium and sodium.
It is desirable to recover both water phase liquid organic compounds as well homogeneous catalysts such as potassium and sodium from the water phase for efficiency as well as economic reasons. Very little information of suitable systems for such recovery and recycling to the feed preparation are disclosed in the prior art.
Iversen (U.S. application Ser. No. 15/787,393) discloses a recovery process, where water phase liquid organic compounds and/or homogeneous catalysts are recovered from the water phase using an evaporation and/or distillation technique.
Although this to some extent provides for a recovery of some of the desired components there are other components that may require purifying in particular the water liquid organic phase.
A general problem of such prior art separation systems is that the separated oil product often contains too high levels of water and inorganics, which limits the quality of the oil (hydrocarbons) and its further use in e.g. catalytic upgrading processes to transportation fuels, lubricants or speciality chemicals.
A general problem in such prior art separation systems is that the water phase often contains too high level of built up contaminants, such as e.g. chlorides, that may have negative effects on the process and the process equipment and as such directly or indirectly may influence the yield obtainable from the process, the quality of the product produced and/or the lifetime of the process equipment.
Accordingly, improved and more efficient separation schemes for purifying/reducing contaminants such as chlorides from the water phase are desirable.